1. Field of the Invention
The present disclosure is directed to a method of manufacturing a thin-film transistor (TFT) substrate, and more particularly, to a method of manufacturing a TFT substrate used for a display device.
2. Description of the Related Art
A liquid crystal display apparatus displaying an image generally includes a thin-film transistor (TFT) substrate having a TFT and a pixel electrode, a color filter substrate having a color filter and a common electrode, and a liquid crystal layer disposed between the TFT substrate and the color filter substrate.
The TFT substrate is manufactured through a photo etching process using a mask. Therefore, to reduce manufacturing costs and improve productivity, the number of processes using the mask can be reduced.
Recently, a four-mask process, through which an active pattern and a data wire are simultaneously patterned using a mask, has been developed. In the four-mask process, a slit mask or a halftone mask is used to form a stepped portion on a surface of a photoresist pattern, and the active pattern and the data wire are simultaneously patterned through a combination of an etching process and an ashing process.
However, the manufacturing cost for the mask is increased in the four-mask process. In addition, the number of processes for manufacturing a TFT substrate may be increased in the four-mask process even though the number of photo processes may be reduced. Since the four-mask process includes an under exposure process, uniformity may be decreased and a precise design may be difficult to manufacture.